How to increase email deliverability?

From this article you will learn what affects the deliverability of emails

Paulina Stężowska avatar
Written by Paulina Stężowska
Updated over a week ago

A few words about e-mail deliverability...

Your deliverability rate shows how many messages were successfully sent to recipients. The average worldwide deliverability is around 79%, while Europe is slightly better — 84% — due to legal restrictions on personal data protection.

This does not change the fact that every sixth message sent will never reach the addressee. According to Return Path research, 6% of sent emails end up in a SPAM folder, while the remaining 10% are not passed through the Internet Service Provider (ISP) filter.

The largest e-mail providers, such as Gmail, care very much about the quality of the e-mails delivered to the recipient. They filter and block spam messages, but at the same time they increase the reach of those "good" emails. Due to the fact the process is automated, anti-spam systems can sometimes misjudge an email.

The good news is that these systems work better and better every day and whether your mail campaigns will "pass" these filters depends mainly on you!

The systems check the recipient's reaction to your mailings, e.g. if most Gmail users mark your message as SPAM, future messages to this provider's mailboxes from the same sender address will have much worse deliverability.

Each sender is assigned a Sender Score, which is an indicator of performance evaluation. It translates directly into deliverability, so you need to make sure that recipient's reactions to your emails are favorable. The Sender Score uses a scale of 1-100. The best senders are usually in the range of 90-100 and their deliverability is kept at 95%.

The best tips for you with deliverability!


SPF is the most important security feature in the world of email marketing. The recipient's email server checks whether the sender's IP address server is authorized to send messages from the given domain.

In short, the SPF confirms that the mail comes from a safe source. You can read more about SPF HERE.
The DKIM signature confirms the sender of the email. This means that the recipient of the message can be sure the sender is the owner of a specific e-mail address and no one is impersonating it. You can read more about DKIM HERE.

Use segmentation!

Emails are more effective when you send your message to a narrow group of recipients instead of to an entire database. Divide your audience into smaller groups, send customized and personalized messages to achieve a higher Open Rate. More about segmentation you can read HERE.

Subscription Model

The Single Opt-In model, with its larger number of subscribers and simpler registration process, can lead to better open and click-through rates for your emails, positively impacting your domain's reputation and future deliverability.

The Double Opt-In model does not guarantee the security of your database. Nowadays, we increasingly encounter bot attacks, which are equally dangerous for your database even with the Double Opt-In model. Implementing appropriate security measures on your website, such as reCAPTCHA, is crucial.

Watch out for SPAM TRAPS!

You don't want your emails to end up in SPAM, do you? As you probably know, successful delivery of your messages can be a long road full of adventure and pitfalls. One of them is SPAM TRAPS. This is when e-mail addresses used by providers and anti-spam organizations "catch" spammers, then blacklist and block them.

Thanks to SPAM TRAPs, mailboxes are protected against unwanted correspondence. SPAM TRAP addresses can also hit your list and significantly affect the reputation and deliverability of your emails... unfortunately, negatively. How can SPAM TRAPS appear in your database?

By buying customer databases from an unreliable source or by the lack of regular database hygiene. You should clean your base and avoid buying contacts from an unknown origin. Follow these two rules and don't let SPAM TRAPs mess up your reachability.

Maintain the hygiene of the contact database

This is a very important element that significantly affects the deliverability and open rate of your emails. Go to reports of your newsletters and analyze recent shipments. How many emails have you sent? How many of them have been opened?

Usually the difference between these values is very large. Some of these unopened messages were sent to so-called "dead contacts'', which means addresses which do not react in any way. Some people just ignore them because they are not interested while others don't use the provided e-mail address anymore, something that is inevitable.

Otherwise you are constantly building your base by collecting new subscribers, so "getting rid" of inactive contacts and replacing them with new ones will only help you!
Read more about database hygiene HERE.

Don't buy a contact database!

You do not know where emails in a purchased database came from — these can be addresses scanned from different sites without the consent of the owners, out of date or simply nonexistent. Often in such databases there are SPAM TRAPs mentioned above.

Even if there are a lot of "live" emails on the purchased list, your mails will not be opened, and thus not effective. Why? Because the recipients of the message will not associate it with your brand, because they did not subscribe to the newsletter on your website.

It is definitely better to spend more time collecting reliable subscribers than to buy lists which only damage your reputation and deliverability.

Hard Bounce!

This means that your message has not been delivered to the addressee. Why? The recipient's address does not exist, the domain name does not exist, or the recipient has blocked delivery of emails. In edrone, we analyze shipments that have received a Hard Bounce notification and we stop sending any messages to such addresses.

Collect subscribers wherever you can!

Place information about the possibility of signing in to the newsletter wherever possible — in the footer of your website, when customers are making a purchase, during user registration, or in a pop-up.

Check this article to read more about collecting subscriber base.

Focus on automation!

Messages tailored to user behavior are very effective. Marketing Automation is activated after a customer action in your store (e.g. abandoning a cart). After receiving such a message, the customer will see we had personalized content sent to him that can help in the purchasing process, it's not another commercial offer.

Automatic messages have high OR and CTR rates. Also, transactional messages come from different provider accounts than marketing messages.

E-mail sender

The messages we send out as a brand should have a human face. "Kate from XYZ" sounds and looks much better than simply "XYZ Company". Additionally, remember the return address should be the same as the sender address. You can check it in any scenario or when creating a newsletter in the "Sender" section. The same e-mail address should be provided in the "From (Email)" and "Reply-to" fields.
Check this article.


is the "gateway" for your mail. What should it be? There is no specific rule, so you need to test and analyze your shipment results and see which topic gives you the highest Open Rate. The topic should be short, catchy and intriguing.

Avoid capital letters and phrases such as: 100%, discount, sale, for free or anything too “salesy”.

You can indicate a limited duration of the offer in the subject - if the recipient finds your message interesting, expired time may increase its attractiveness. Encourage recipients to respond through action verbs.

Unsubscribe link

Each e-mail sent with edrone includes the option to unsubscribe at the bottom of the message:

However, you should add one more clear and visible option to unsubscribe using the unsubscribe link - in content of your mail, for example in the footer:

Customers who don't want to receive messages from you have the opportunity to simply unsubscribe instead of marking mails as SPAM.


This action is very positively assessed by anti-spam filters. What should you do? Create your offers in an attractive way so recipients will want to share them with others.

You can offer group discounts or simply ask them to forward the message. For example, when you are creating a promotional newsletter for Valentine’s Day, add an invitation: "Pass this message to your friends so they do not forget about a gift for their loved one!"

Reply to

Put a human face on your conversation! Show your audience there is a real person on the other side who wants to communicate with them, not only send one-way information.

Use CTA communication. For example: "Have you got any questions? We will be happy to answer", "Can we help you?", "Tell us, what can we change? We want to improve ourselves for you", etc. Using such messages you build a good relationship with your customers!

Images and text

Use the 40/60 rule: 40% graphics and 60% text. If you want to increase the deliverability of your messages, definitely mail should not be one huge image. A graphically attractive mail gets attention, but it is worth considering how many people it will reach. It is good to separate graphics with equally alluring copy or buttons.

Dedicated IP address

You work on the credibility of your emails and the reputation of your IP. A dedicated IP ensures exclusivity and security. It will allow you to avoid many of the inconveniences of using a shared IP address.


This is an HTML tag which is an alternative description of image. It is possible to describe the content of an image, which is important for positioning because it informs search engines about the subject of the image. Alternative text also provides information to the recipients of a message/ website, if the image cannot be displayed.

Sending time

Messages sent while the recipient is most likely to check their inboxes can be noticed and read more easily. So when is the best time to send newsletters? There is no fixed answer. Try to test different daily and hourly variants, analyze the Open Rate and find out the days and hours when recipients are the most likely to open your message.

Resend Campaign

Send the message again to those who haven't opened it previously. Sometimes it is enough to make slight corrections to the subject and your email will be noticed. Find out how to create a Resend Campaign in edrone HERE.

Test your shipments!

Check the correctness of your emails. You can do it in a simple way, by using the mail-tester website -

As you can see, there are many factors that affect the deliverability and open rates of your emails. Implement these tips and help your messages reach the largest possible audience!

Need more help?
If you have more questions about deliverability your emails, do not hestiate to contact us at

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